In fuel supply devices that supply fuel inside a fuel tank to an external device such as an engine, fuel supply devices exist that are provided with a fuel filter inside a fuel tank body, and that feed out fuel, from which the fuel filter has removed foreign matter, to the exterior of the fuel tank body. For example, Japanese Patent Application Laid-Open (JP-A) No. H6-317286 describes a fuel filter device with an internal space configured between a first member and a second member, and with a filter member interposed between the first member and the second member.
However, in the structure of the filter described in Patent Document 1, since the filter members are not in close contact with each other, there is a concern that an oil membrane could break, and gas could flow into the space between the filter members, when for example an upper side filter member is no longer in contact with the fuel. Simply joining together the plural filter members may be considered in order to suppress this eventuality, however since external forces sometimes act on the joint portion through the first member and/or the second member, it is desirable to maintain the strength of the joint.